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Razavinia, Nasimalsadat. "Waste heat recovery with heat pipe technology". Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=94983.
Pełny tekst źródłaL'énergie d'haut grade de nos jours est produite principalement à base de combustion d'hydrocarbure et les réserves de cette énergie deviennent de plus en plus rare, mais certaines énergies alternatives connues gagnent des forces parmi les marchés incluant les sources d'énergie renouvelables et recyclées. Les usines pyrométallurgiques sont des consommateurs significatifs d'énergie d'haut grade. Ces procédés industriels relâches un montant important de chaleurs (perte) à l'environnement sans aucune récupération. Le but du projet est de concentrer, capturer et convertir cette chaleur résiduelle de basse qualité en énergie valable. Par contre, l'objectif principal du projet comme tel est de développer et de perfectionner un caloduc capable d'extraire cette chaleur parvenant des gaz effluents. Le point d'ébullition d'une substance (vapeur) est utilisé comme moyen de concentrer l'énergie contenu dans les effluents avec la technologie des caloducs. Pour maximiser les gains énergétiques, la conception de ce caloduc en particulier utilise des canaux de retour indépendant ainsi qu'un modificateur de débit dans l'évaporateur, lui permettant d'extraire un niveau supérieur de chaleur. Pendant les essais lors du projet, les éléments limitants des systèmes de caloducs ont été identifiés. Les configurations du système ont été ajustées et modifiés dans la phase expérimentale d'essai pour surmonter ces limitations et maximiser l'extraction de chaleur.
Nyholm, Joakim. "Horizontal wastewater heat recovery heat exchanger, a model". Thesis, KTH, Energiteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-263618.
Pełny tekst źródłaByggnads och servicesektorn står för cirka 40 procent av Sveriges energibehov. Av de 40 procenten består 90% av energibehov ifrån hushåll och kontorsbyggnader. Totalt sett 80 TWh används för uppvärmning av byggnader samt varmvatten. Då uppvärmning alltid varit en stor del av energibehovet i Sverige är det naturligt att det skett en rad förbättringar på vägen. Det finns en ny anläggning på Pennfäktaren 11 i Stockholm, en horisontell värmeväxlare för avloppsvatten. Den här uppsatsen fokuserar på att skapa en modell i TRNSYS av en värmeväxlare där parametrar som vattenflöde, temperatur, och mer kan användas för att bedöma den tekniska aspekten av en installation av värmeväxlare i en byggnad. Modellen kan simulera prestandan av en ensam värmeväxlare, med endast ett fåtal parametrar som behövs. Modellen baseras på mätdata ifrån anläggningen på Pennfäktaren, denna mätdata har sedan använts för att beräkna först massflödet av avloppsvatten men också för att bestämma hur mycket värme som är möjligt att återvinna utan att överskrida det byggnaden faktiskt kan använda. Då det bara finns data ifrån en källa fick den anses som korrekt, dock gjordes en del ändringar där data helt enkelt var omöjligt, t.ex. negativa avloppsflöden och flödesmängder så höga att de inte ska kunna vara möjliga. Den färdiga modellen använder mätdata tillsammans med de beräknade värdena. Detta används för att genom modellen beräkna temperaturvärden för utgående vatten och avlopp samt den totala mängden återvunnen värme. I referensscenariot kunde totalt 25,3 MWh värme återvinnas men det bästa scenariot med ökad avloppstemperatur och avloppsflöde kunde närmare 47,2 MWh återvinnas, nästan det dubbla från referensvärdet. För att sammanfatta ger modellens simulationer rimliga värden för värmeväxlaren. Det bör därför vara fullt möjligt att använda modellen för att bedöma ett hus rimlighet till en värmeväxlarinstallation.
Staats, Wayne Lawrence. "Active heat transfer enhancement in integrated fan heat sinks". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78179.
Pełny tekst źródłaThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 205-211).
Modern computer processors require significant cooling to achieve their full performance. The "efficiency" of heat sinks is also becoming more important: cooling of electronics consumes 1% of worldwide electricity use by some estimates. Unfortunately, current cooling technologies often focus on improving heat transfer at the expense of efficiency. The present work focuses on a unique, compact, and efficient air cooled heat sink which addresses these shortcomings. While conventional air cooled heat sinks typically use a separate fan to force air flow over heated fins, the new design incorporates centrifugal fans directly into the body of a loop heat pipe with multiple planar condensers. These "integrated fans" rotate between the planar condensers, in close proximity to the hot surfaces, establishing a radially outward flow of cooling air. The proximity of the rotating impellers to the condenser surfaces results in a marked enhancement in the convective heat transfer coefficient without a large increase in input power. To develop an understanding of the heat transfer in integrated fan heat sinks, a series of experiments was performed to simultaneously characterize the fan performance and average heat transfer coefficients. These characterizations were performed for 15 different impeller profiles with various impeller-to-gap thickness ratios. The local heat transfer coefficient was also measured using a new heated-thin-film infrared thermography technique capable of applying various thermal boundary conditions. The heat transfer was found to be a function of the flow and rotational Reynolds numbers, and the results suggest that turbulent flow structures introduced by the fans govern the transport of thermal energy in the air. The insensitivity of the heat transfer to the impeller profile decouples the fan design from the convection enhancement problem, greatly simplifying the heat sink design process. Based on the experimental results, heat transfer and fan performance correlations were developed (most notably, a two-parameter correlation that predicts the dimensionless heat transfer coefficients across 98% of the experimental work to within 20% relative RMS error). Finally, models were developed to describe the scaling of the heat transfer and mechanical power consumption in multi-fan heat sinks. These models were assessed against experimental results from two prototypes, and suggest that future integrated fan heat sink designs can achieve a 4x reduction in thermal resistance and 3x increase in coefficient of performance compared to current state-of-the-art air cooled heat sinks.
by Wayne L. Staats, Jr.
Ph.D.
Meyer, Meyer. "Development of a range of air-to-air heat pipe heat recovery heat exchangers". Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16389.
Pełny tekst źródłaENGLISH ABSTRACT: As the demand for less expensive energy is increasing world-wide, energy conservation is becoming a more-and-more important economic consideration. In light of this, means to recover energy from waste fluid streams is also becoming more-and-more important. An efficient and cost effective means of conserving energy is to recover heat from a low temperature waste fluid stream and use this heat to preheat another process stream. Heat pipe heat exchangers (HPHEs) are devices capable of cost effectively salvaging wasted energy in this way. HPHEs are liquid-coupled indirect transfer type heat exchangers except that the HPHE employs heat pipes or thermosyphons as the major heat transfer mechanism from the high temperature to the low-temperature fluid. The primary advantage of using a HPHE is that it does not require an external pump to circulate the coupling fluid. The hot and cold streams can also be completely isolated preventing cross-contamination of the fluids. In addition, the HPHE has no moving parts. In this thesis, the development of a range of air-to-air HPHEs is investigated. Such an investigation involved the theoretical modelling of HPHEs such that a demonstration unit could be designed, installed in a practical industrial application and then evaluated by considering various financial aspects such as initial costs, running costs and energy savings. To develop the HPHE theoretical model, inside heat transfer coefficients for the evaporator and condenser sections of thermosyphons were investigated with R134a and Butane as two separate working fluids. The experiments on the thermosyphons were undertaken at vertical and at an inclination angle of 45° to the horizontal. Different diameters were considered and evaporator to condenser length ratios kept constant. The results showed that R134a provided for larger heat transfer rates than the Butane operated thermosyphons for similar temperature differences despite the fact that the latent heat of vaporization for Butane is higher than that of R134a. As an example, a R134a charged thermosyphon yielded heat transfer rates in the region of 1160 W whilst the same thermosyphon charged with Butane yielded heat transfer rates in the region of 730 W at 23 °C . Results also showed that higher heat transfer rates were possible when the thermosyphons operated at 45°. Typically, for a thermosyphon with a diameter of 31.9 mm and an evaporator to condenser length ratio of 0.24, an increase in the heat transfer rate of 24 % could be achieved. Theoretical inside heat transfer coefficients were also formulated which were found to correlate reasonably well with most proposed correlations. However, an understanding of the detailed two-phase flow and heat transfer behaviour of the working fluid inside thermosyphons is difficult to model. Correlations proposing this behaviour were formulated and include the use of R134a and Butane as the working fluids. The correlations were formulated from thermosyphons of diameters of 14.99 mm, 17.272 mm, 22.225 mm and 31.9 mm. The evaporator to condenser length ratio for the 31.9 mm diameter thermosyphon was 0.24 whilst the other thermosyphons had ratios of 1. The heat fluxes ranged from 1800-43500 W/m2. The following theoretical inside heat transfer coefficients were proposed for vertical and inclined operations (READ CORRECT FORMULA IN FULL TEXT ABSTRACT) φ = 90° ei h = 3.4516x105Ja−0.855Ku1.344 φ = 45° ei h = 1.4796x105Ja−0.993Ku1.3 φ = 90° l l l ci l l v h x k g 1/ 3 2.05 2 4.61561 109Re 0.364 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ φ = 45° l l l ci l l v h x k g 1/ 3 1.916 2 3.7233 10 5Re 0.136 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ The theoretically modelled demonstration HPHE was installed into an existing air drier system. Heat recoveries of approximately 8.8 kW could be recovered for the hot waste stream with a hot air mass flow rate of 0.55 kg/s at an inlet temperature of 51.64 °C and outlet temperature of 35.9 °C in an environment of 20 °C. Based on this recovery, energy savings of 32.18 % could be achieved and a payback period for the HPHE was calculated in the region of 3.3 years. It is recommended that not withstanding the accuracies of roughly 25 % achieved by the theoretically predicted correlations to that of the experimental work, performance parameters such as the liquid fill charge ratios, the evaporator to condenser length ratios and the orientation angles should be further investigated.
AFRIKAANSE OPSOMMING: As gevolg van die groeiende aanvraag na goedkoper energie, word die behoud van energie ‘n al hoe belangriker ekonomiese oorweging. Dus word die maniere om energie te herwin van afval-vloeierstrome al hoe meer intensief ondersoek. Een effektiewe manier om energie te herwin, is om die lae-temperatuur-afval-vloeierstroom (wat sou verlore gaan) se hitte te gebruik om ‘n ander vloeierstroom mee te verhit. Hier dien dit dan as voorverhitting van die ander, kouer, vloeierstroom. Hittepyp hitteruilers (HPHR’s) is laekoste toestelle wat gebruik kan word vir hierdie doel. ‘n HPHR is ‘n vloeistof-gekoppelde indirekte-oordrag hitteruiler, behalwe vir die feit dat dié hitteruiler gebruik maak van hittepype (of hittebuise) wat die grootste deel van sy hitteoordragsmeganisme uitmaak. Die primêre voordele van ‘n HPHR is dat dit geen bewegende dele het nie, die koue- en warmstrome totaal geïsoleer bly van mekaar en geen eksterne pomp benodig word om die werkvloeier mee te sirkuleer nie. In hierdie tesis word ‘n ondersoek gedoen oor die ontwikkeling van ‘n bestek van lug-totlug HPHR’s. Hierdie ondersoek het die teoretiese modellering van so ‘n HPHR geverg, sodat ‘n demonstrasie eenheid ontwerp kon word. Hierdie demonstrasie eenheid is geïnstalleer in ‘n praktiese industriële toepassing waar dit geïvalueer is deur na aspekte soos finansiële voordele en energie-besparings te kyk. Om die teoretiese HPHR model te kon ontwikkel, moes daar gekyk word na die binnehitteoordragskoëffisiënte van die verdamper- en kondensordeursneë, asook R134a en Butaan as onderskeie werksvloeiers. Die eksperimente met die hittebuise is gedoen in die vertikale en 45° (gemeet vanaf die horisontaal) posisies. Verskillende diameters is ook ondersoek, maar met die verdamper- en kondensor-lengteverhouding wat konstant gehou is. Die resultate wys dat R134a as werksvloeier in die hittebuise voorsiening maak vir groter hitteoordragstempo’s in vergelyking met Butaan as werksvloeier by min of meer dieselfde temperatuur verskil – dít ten spyte van die feit dat Butaan ‘n hoër latente-hittetydens- verdampings eienskap het. As voorbeeld gee ‘n R134a-gelaaide hittebuis ‘n hitteoordragstempo van omtrent 1160 W terwyl dieselfde hittebuis wat met Butaan gelaai is, slegs ongeveer 730 W lewer by 23 °C. Die resultate wys ook duidelik dat hoër hitteoordragstempo’s verkry word indien die hittebuis bedryf word teen ‘n hoek van 45°. ‘n Tipiese toename in hitteoordragstempo is ongeveer 24 % vir ‘n hittebuis met ‘n diameter van 31.9 mm en ‘n verdamper- tot kondensor-lengteverhouding van 0.24. Teoretiese binne-hitteoordragskoëffisiënte is ook geformuleer. Dié waardes stem redelik goed ooreen met die meeste voorgestelde korrelasies. Nieteenstaande die feit dat gedetailleerde twee-fase-vloei en die hitteoordragsgedrag van die werksvloeier binne hittebuise nog nie goed deur die wetenskaplike wêreld verstaan word nie. Korrelasies wat hierdie gedrag voorstel is geformuleer en sluit weereens die gebruik van R134a en Butaan as werksvloeiers in. Die korrelasies is geformuleer vanaf hittebuise met diameters van onderskeidelik 14.99 mm, 17.272 mm, 22.225 mm en 31.9 mm. Die verdamper- tot kondensor-lengteverhoudings vir die 31.9 mm deursnit hittebuis was 0.24 terwyl die ander hittebuise ‘n verhouding van 1 gehad het. Die hitte-vloede het gewissel van 1800-45300 W/m2. Die volgende teoretiese geformuleerde binne-hitteoordragskoëffisiënte word voorgestel vir beide vertikale sowel as nie-vertikale toepassing (LEES KORREKTE FORMULE IN VOLTEKS OPSOMMING) φ = 90° ei h = 3.4516x105Ja−0.855Ku1.344 φ = 45° ei h = 1.4796x105Ja−0.993Ku1.3 φ = 90° l l l ci l l v h x k g 1/ 3 2.05 2 4.61561 109Re 0.364 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ φ = 45° l l l ci l l v h x k g 1/ 3 1.916 2 3.7233 10 5Re 0.136 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ Die wiskundig-gemodelleerde demostrasie HPHR is geïnstalleer binne ‘n bestaande lugdroër-sisteem. Drywing van om en by 8.8 kW kon herwin word vanaf die warm-afvalvloeierstroom met ‘n massa vloei van 0.55 kg/s teen ‘n inlaattemperatuur van 51.64 °C en ‘n uitlaattemperatuur van 35.9 °C binne ‘n omgewing van 20 °C. Na aanleiding van hierdie herwinning, kan energiebesparings van tot 32.18 % verkry word. Die HPHR se installasiekoste kan binne ‘n berekende tydperk van ongeveer 3.3 jaar gedelg word deur hierdie besparing. Verdamper- tot kondensator-lengteverhouding, vloeistofvulverhouding en die oriëntasiehoek vereis verdere ondersoek, aangesien daar slegs ‘n akkuraatheid van 25 % verkry is tussen teoretiese voorspellings en praktiese metings.
Phillips, Bren Andrew. "Nano-engineering the boiling surface for optimal heat transfer rate and critical heat flux". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76536.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (p. 130-133).
The effects on pool boiling characteristics such as critical heat flux and the heat transfer coefficient of different surface characteristics such as surface wettability, roughness, morphology, and porosity are not well understood. Layer-by-layer nanoparticle coatings were used to modify the surface of a sapphire heater to control the surface roughness, the layer thickness, and the surface chemistry. The surface was then tested in a water boiling test at atmospheric pressure while imaging the surface with high speed infrared thermography yielding a 2D time dependent temperature profile. The critical heat flux and heat transfer coefficient were enhanced by over 100% by optimizing the surface parameters. It was found that particle size of the nanoparticles in coating, the coating thickness, and the wettability of the surface have a large impact on CHF and the heat transfer coefficient. Surfaces were also patterned with hydrophobic "islands" within a hydrophilic "sea" by coupling the Layer-by-layer nanoparticle coatings with an ultraviolet ozone technique that patterned the wettability of the surface. The patterning was an attempt to increase the nucleation site density with hydrophobic dots while still maintaining a large hydrophilic region to allow for rewetting of the surface during the ebullition cycle and thus maintaining a high critical heat flux. The patterned surfaces exhibited similar critical heat fluxes and heat transfer coefficients to the surfaces that were only modified with layer-by-layer nanoparticle coatings. However, the patterned surfaces also exhibited highly preferential nucleation from the hydrophobic regions demonstrating an ability to control the nucleation site layout of a surface and opening an avenue for further study.
by Bren Andrew Phillips.
S.M.
Sivanantharaja, G. (Geethanchali). "Effect of surface roughness on heat transfer in heat exchanger". Bachelor's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201712143310.
Pełny tekst źródłaLämmönvaihdin on laite, joka siirtää lämpöä fluidista toiseen tai fluidin ja ympäristön välillä. Viimeisimpien vuosikymmenten aikana lämmönvaihtimien rooli on kasvanut lämmön talteenottoprosesseissa ja uusien energialähteiden käyttöönotossa. Lämmönvaihtimien pinnankarheudella, jolla tarkoitetaan seinämän pintakuvion korkeuden muutosta verrattuna tasaiseen pintaan, on merkittävä rooli lämmönvaihtimen tehokkuudessa. Pinnankarheuden vaikutusta lämmönsiirtoon onkin tarkasteltu useissa tutkimuksissa. Pinnankarheus voi olla osa lämmönvaihdinrakennetta tai johtua ei haluttujen materiaalien kerrostumisesta pinnalle. Tällöin puhutaan likaantumisesta, joka heikentää lämmönvaihtimen lämmönsiirtoa, lisää painehäviötä ja voi aiheuttaa korroosiota. Dimensiottomat korrelaatiot, kuten Nusseltin luku antavat tietoa pinnankarheuden aiheuttamasta vaikutuksen lämmönsiirtoon. Tässä kandidaatintyössä on tarkasteltu kirjallisuudessa esitettyjä Nusseltin luvun korrelaatioita ja niiden soveltuvuutta eri pinnankarheuden muotoihin sekä tutkittu niiden soveltuvuutta todellisen lämmönvaihtimen tapauksessa. Tästä tutkimuksessa tarkastelluista korrelaatioista Nunnerin korrelaatio soveltui parhaiten likaantuneen lämmönvaihtimen lämmönsiirron tarkasteluun. Sainin ym. korrelaatio arvioitiin soveltuvan paremmin keinotekoisen pinnankarheuden kuin likaantuneen pinnan lämmönsiirron tarkasteluun
Behbahani, Reza M. "Heat transfer and heat transfer fouling in phosphoric acid evaporators". Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/842710/.
Pełny tekst źródłaHolzaepfel, Gregory M. "Convective Heat Transfer in Parallel Plate Heat Sinks". Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1292521397.
Pełny tekst źródłaGari, Abdullatif Abdulhadi. "Analysis of conjugate heat transfer in tube-in-block heat exchangers for some engineering applications". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001716.
Pełny tekst źródłaBotos, Peter A. (Peter Alex). "The heat pipe injection lance /". Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56782.
Pełny tekst źródłaDelattre, Baptiste. "Monitoring of a heat pump system using deep borehole heat exchangers". Thesis, KTH, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-245880.
Pełny tekst źródłaSverige var ett av de första länderna i världen som använt bergvärmepumpar (GSHP) för att täcka värme- och kylbehoven i byggnader. Sverige är, idag, det ledande landet i Europa och nya bergvärmeanläggningar tenderar att vara större, åtminstone kapacitetsmässigt. Användningen av djupa borrhålsvärmeväxlare (BHEs) ger möjligheten att extrahera en större mängd värme i areabegränsade egendomar. Det finns dock bara få studiefall om anläggningar med borrhål djupare än 300 m och de anläggningarna skulle därför kunna optimeras. Den här studien fokuserar på ett GSHP system med djupa borrhål som nyligen installerades i centrala Stockholm och som består av fyra 510 m djupa borrhål, bland annat. Målen var att förberedda prestandauppföljningssystemet och analysera de första insamlade mätningarna. Första steget var att samla information om de sensorerna som redan var installerade, bestämma vilka mätvärde var nödvändiga och hur skulle de kunna mättas. Praktiskt har en datainsamlingsenhet iordningställts och anslutits till befintliga och nya sensorer såsom temperaturgivare och flödesmätare. Teoretiskt har en metod frambringats för att bestämma den termodynamiska cykeln av varje värmepump. Det möjliggjorde beräkningen av COP:n under vissa dagar under våren 2017. Globalt visade systemet rimlig prestanda med en prestandafaktor (likvärdig SPF2) på 3.42, inklusive cirkulationspumpar i bergvärmeskretsen. Det skulle dock kunna förbättras på olika sätt, t.ex. genom att undvika kort-cykling av kompressorer eller gnom att hitta ett optimalt köldbärarflöde i bergvärmeskretsen. Resultaten som det här arbetet kom fram till borde dessutom jämföras med en liknande analys under vintertid, då värmebehovet är högst.
De, Waal Devin. "Feasibility study of heat pumps for waste heat recovery in industry". Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/10324.
Pełny tekst źródłaA case study was thus carried out at an applicable local industry (brewery) to assess the feasibility of implementing the heat pump for waste heat recovery. Through analysis, the focus was narrowed down from a site wide audit, to a departmental breakdown and then eventually to a specific process; the wort boiler. Three different alternatives were investigated and the performance and economic viability compared; a simple waste heat recovery solution involving a vapour condenser (vq, a mechanical vapour recompression (MVR) heat pump and a thermal vapour recompression (TVR) heat pump. It was found that the MVR system yielded the greatest energy savings, followed by the VC and then the TVR system. All three systems had positive rates of return, with the VC and TVR systems being tied for first place.
Yang, Jun. "Effect of non-uniform axial heat-flux distribution on critical heat flux". Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26816.
Pełny tekst źródłaZhang, Xingxing. "Investigation of a novel solar photovoltaic/loop-heat-pipe heat pump system". Thesis, University of Hull, 2014. http://hydra.hull.ac.uk/resources/hull:8422.
Pełny tekst źródłaWalker, Jacob D. "Heat Transfer Analysis of Localized Heat-Treatment for Grade 91 Steel". DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6045.
Pełny tekst źródłaHong, Vu Anh. "Bacteria mediated heat sinks". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59931.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (p. 55).
Many applications, such as laser diode technology, utilize components (eg. resistors) which have performance characteristics heavily dependent on temperature, and therefore, maintaining constant temperature is essential in order to eliminate drift in device efficiency. Constant temperature controllers, however, can often be complicated and only stay within a certain range of a set temperature. If temperature needs to be maintained, this thesis suggests a model instead to use ice as an isothermal heat sink. The model proposes to make use of thermodynamics and stabilize an isothermal solid-liquid interface created during ice formation, which will lead to having an isothermal free surface in the liquid phase. The model was validated using a Peltier device to freeze water by applying a constant DC current, and because the inefficiency of the module decreases with decreasing temperature, the heat dissipating power of the thermoelectric eventually equalizes with the ambient losses, stabilizing a solid-liquid interface. This stabilized interface was able to be maintained in experiments using deionized (DI) water, DI water with polystyrene (PS) micro-beads, and DI water with Pseudomonas syringae, a gram-negative bacteria. Pseudomonas syringae is known as an ice-nucleating agent that can reduce the amount of supercooling needed to nucleate ice. Experiments using the bacteria were observed to stabilize a solid-liquid interface faster than the control experiments, and this phenomenon was modeled as a two-fold reason: (1) by increasing nucleation temperature using the bacteria, a reduced input Peltier power is needed to nucleate ice, thereby making the Peltier device reach the steady-state heat losses faster; and (2) a possible decreased enthalpy of fusion caused by the bacteria leads to less latent heat released during the freezing process, putting less heat load on the Peltier device and allowing it to reach steady-state faster. This prediction regarding decreased enthalpy of fusion was validated using a heat flux sensor, as the preliminary results for a mixture of DI water with bacteria yielded an enthalpy of fusion of (199.1±20.2) kJ/kg, whereas the values for DI water and DI water with PS beads were (345.1±15.6) kJ/kg and (328.3±31.2) kJ/kg respectively.
by Vu Anh Hong.
S.B.
Veijola, T. (Tommi). "Domestic wastewater heat recovery". Bachelor's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201704271600.
Pełny tekst źródłaTaposh, Rahat M. "Optimization of Heat Spreader". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1337729321.
Pełny tekst źródłaXue, Xingjian. "IMPROVEMENTS ON HEAT FLUX AND HEAT CONDUCTANCE ESTIMATION WITH APPLICATIONS TO METAL CASTINGS". MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-08042003-091324/.
Pełny tekst źródłaLiu, Xin. "Liquid jet impingement heat transfer and its potential applications at extremely high heat fluxes". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13066.
Pełny tekst źródłaNajibi, Seyed Hesam. "Heat transfer and heat transfer fouling during subcooled flow boiling for electrolyte solutions". Thesis, University of Surrey, 1997. http://epubs.surrey.ac.uk/773/.
Pełny tekst źródłaTong, Jonathan Kien-Kwok. "Photonic engineering of near- and far-field radiative heat transfer". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104127.
Pełny tekst źródłaThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 181-195).
Radiative heat transfer is the process by which two objects exchange thermal energy through the emission and absorption of electromagnetic waves. It is one of nature's key fundamental processes and is ubiquitous in all facets of daily life from the light we receive from the Sun to the heat we feel when we place our hands near a fire. Fundamentally, radiative heat transfer is governed by the photonic dispersion, which describes all the electromagnetic states that can exist within a system. It can be modified by the material, the shape, and the environment. In this thesis, morphological effects are used to modify the photonic dispersion in order to explore alternative methods to spectrally shape, tune, and enhance radiative heat transfer from the near-field to the far-field regimes. We start by investigating the application of thin-film morphologies to different types of materials in the near-field regime using a rigorous fluctuational electrodynamics formalism. For thin-film semiconductors, trapped waveguide modes are formed, which simultaneously enhance radiative transfer at high frequencies where these modes are resonant and suppress radiative transfer at low frequencies where no modes are supported. This spectrally selective behavior is applied to a theoretical thermophotovoltaics (TPV) system where it is predicted the energy conversion efficiency can be improved. In contrast, thin-films of metals supporting surface plasmon polariton (SPP) modes will exhibit the opposite effect where the hybridization of SPP modes on both sides of the film will lead to a spectrally broadened resonant mode that can enhance near-field radiative transfer by over an order of magnitude across the infrared wavelength range. In order to observe these morphological spectral effects, suitable experimental techniques are needed that are capable of characterizing the spectral properties of near-field radiative heat transfer. To this end, we developed an experimental technique that consists of using a high index prism in an inverse Otto configuration to bridge the momentum mismatch between evanescent near-field radiative modes and propagation in free space in conjunction with a Fourier transform infrared (FTIR) spectrometer. Preliminary experimental results indicate that this method can be used to measure quantitative, gap-dependent near-field radiative heat transfer spectrally. While utilizing near-field radiative transfer remains a technologically challenging regime for practical application, morphological effects can still be used to modify the optical properties of materials in the far-field regime. As an example, we use polyethylene fibers to design an infrared transparent, visibly opaque fabric (ITVOF), which can provide personal cooling by allowing thermal radiation emitted by the human body to directly transmit to the surrounding environments while remaining visible opaque to the human eye.
by Jonathan Kien-Kwok Tong.
Ph. D.
Storm, Josefin. "Heat Transfer Modeling for Turbocharger Control". Thesis, Linköpings universitet, Fordonssystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-141949.
Pełny tekst źródłaAl-Waaly, Ahmed. "The effect of heat transfer on temperature measurement and its applications to study microchannel heat sinks". Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6781/.
Pełny tekst źródłaHodgson, David K. "The Post Weld Heat Treatment Response in the Heat Affected Zone of 2.25Cr-1Mo Steel". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1367416587.
Pełny tekst źródłaNordell, Bo. "Borehole heat store design optimization". Doctoral thesis, Luleå tekniska universitet, Arkitektur och vatten, 1994. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26447.
Pełny tekst źródłaGodkänd; 1994; 20070209 (ysko)
Mahfoud, Musbah. "Controlled thermal analysis using heat pipe technology". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34663.
Pełny tekst źródłaTo overcome these shortcomings associated with current thermal analysis methods, a new technique of performing thermal analysis on aluminum alloys has been devised. Besides being semi-continuous, the new system is easier to use, more dependable and, most importantly, capable of performing thermal analysis tests at controlled and variable cooling rates throughout the entire solidification process.
The new thermal analysis technique is based on heat pipe principles in which a small quantity of a melt, residing in the core of a heat pipe probe, is solidified, and its cooling curve is acquired. Once the cooling curve has been acquired, the probe is instructed to remelt the sample and await instructions to run another test. The new probe, which resides in the melt and need not be withdrawn, is used to solidify the sample under predetermined and controlled conditions.
The operating principles of the new thermal analysis device are based on heat pipe technology. In simple terms, a heat pipe is a high heat transfer device capable of transferring large amounts of heat from a source to a sink by taking advantage of the high heat transfer rates associated with the evaporation and condensation of a working fluid placed inside the pipe. Heat is absorbed at the heat source (evaporator) and dissipated at the heat sink (condenser) at approximately isothermal conditions, and hence the thermal gradient from one extreme end of the pipe to the other is minimal, the amount of heat transferred is large, and the thermal resistance is small.
The new thermal analysis device has been used to produce cooling curves of various aluminum alloys. The device has also been shown to detect the extent of grain refinement, degree of eutectic modification, and formation of intermetallic phases. In addition, the device has been used to quantify the amount of iron in aluminum melts. Thermal analysis results obtained with the new technique are in good agreement with those of conventional thermal analysis. In conjunction with the new device, a control scheme has been devised to control the heat extraction and cooling rates during cooling of aluminum alloys. Finally, a heat transfer and solidification model of the heat pipe thermal analyzer is derived and validated based on the acquired experimental data.
Thermal analysis results are reported for pure aluminum, three casting alloys: hypeoeutectic aluminum silicon (A356 and A319), and a eutectic aluminum silicon (413) alloy, and a wrought alloy of the 6000 series (6061).
Piesciorovsky, Emilio Carlos. "Heat gain from power panelboard". Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2348.
Pełny tekst źródłaZahlan, Hussam. "Flow obstacle effect on film boiling heat transfer with uniform and non-uniform axial heat flux". Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28143.
Pełny tekst źródłaGupta, Jatin. "Application Of Conjugate Heat Transfer (Cht) Methodology For Computation Of Heat Transfer On A Turbine Blade". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1230064860.
Pełny tekst źródłaLee, Jeongik. "Gas heat transfer in a heated vertical channel under deteriorated turbulent heat transfer regime". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41296.
Pełny tekst źródłaIncludes bibliographical references (p. 283-289).
Passive cooling via natural circulation of gas after a loss of coolant (LOCA) accident is one of the major goals of the Gas-cooled Fast Reactor (GFR). Due to its high surface heat flux and low coolant velocities under natural circulation in post-LOCA scenarios, the capability of turbulent gas flow to remove heat from the GFR core can be impaired by either a buoyancy effect or an acceleration effect. These phenomena lead to a Deteriorated Turbulent Heat Transfer (DTHT) regime. To predict accurately the cladding temperature at the hot spot, reliable heat transfer correlations that account correctly for these effects are needed. This work addresses this need by experimentally obtaining heat transfer data and developing new heat transfer correlations that can be used in system analysis codes, such as RELAP5-3D, to reduce uncertainties of predictions in these DTHT regimes. An experimental facility was designed and built using similitude analysis to match key experimental loop parameters to the GFRs' Decay Heat Removal (DHR) system operating conditions to the largest extent possible. Through a thorough literature survey two non-dimensional numbers namely (1) the buoyancy parameter (Bo*) and (2) the acceleration parameter (K,) were identified as important indicators of the DTHT regime. The experimental data was collected for a range of (1) inlet Reynolds number from 1800 to 42,700, (2) inlet Bo* up to 1X10-5 (3) and inlet Kv up to 5x10-6. The data showed significantly higher reduction of the Nusselt number (up to by 70%) than previously reported (up to 50%). Also, the threshold at which DTHT regime occurs was found to be at smaller non-dimensional numbers than previously reported. A new phenomenon "re-turbulization", where the laminarized heat transfer recovers back to turbulent flow along the channel, was observed in the experiment.
(cont.) A new single phase gas flow heat transfer map is proposed based on the non-dimensional heat flux and the Reynolds number in our data, and is shown to compare well with data in the literature. Three sets of new correlations were developed, which reflect both the buoyancy and acceleration effects and have better accuracy as well as ease of numerical implementation than the existing correlations. The correlations are based on the Gnielinski correlation and replace the Reynolds number subtracting constant by a functional form that accounts for the buoyancy and acceleration effects separately, or in the combined form through a newly introduced non-dimensional "DTHT" number. The three correlation types have different complexity level, with the first being the most complex and the third being the most simple and easy to apply without any need for iterations. Additional runs with natural circulation showed that the friction factor in the DTHT regime could be significantly higher than predicted by conventional friction factor correlations, although more experiments will be needed to develop reliable correlations for pressure drop in these regimes. Overall, it is concluded that due to the low heat transfer coefficient and increased friction factor in the DTHT regime, the GFR DHR system should be ideally designed to operate outside the DTHT regime to (1) avoid reduction of heat transfer capability, (2) avoid increase of pressure drop, and (3) reduce uncertainties in predictions of the cladding temperature.
by Jeongik Lee.
Ph.D.
Nordlöf, Anon, i John Lundqvist. "Turbo Heat Transfer Modeling for Control". Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-150352.
Pełny tekst źródłaJin, Ze. "Conjugated heat transfer in crossflow boiling". Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/5803.
Pełny tekst źródłaGuellouz, Mohamed Sadok. "Heat transfer in rod bundle subchannels". Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5960.
Pełny tekst źródłaLedermann, Thomas H. "Submerged mold casting using heat pipes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44006.pdf.
Pełny tekst źródłaLee, JuHee 1973. "Flow modification in McGill Heat Pipes". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82608.
Pełny tekst źródłaThis thesis describes how the McGill heat pipe was developed, tested, modeled and applied in high heat flux situations. Until the development of the McGill Heat Pipe, three main issues had prevented the successful use of heat pipe technology in high heat flux applications. These relate to limitations imposed by film boiling, dry-out, and the structure of the flow. The McGill Heat Pipe has successfully addressed and overcome these limitations.
To overcome film boiling and dry-out, a flow modifier was developed. The structure of the flow was changed by introducing a reservoir and a return line. This thesis describes some of the work that is being carried out to develop and evaluate families of flow modifiers, or spiral springs. Results from a number of high flux experiments will be detailed and the effects of the flow modifiers for each case will be described. In addition, the velocity of the return water was visualized with magnesium alloy chips and was measured with a video camera. Comparisons of the operation of the heat pipe both with and without a flow modifier are presented. This is the first study of its kind in which a transparent glass return line and particles were used to visualize the liquid flow in the return line of the heat pipe.
Min, Byung Kyu. "Heat loss in MHTGR upper plenum". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/38717.
Pełny tekst źródłaLee, Victoria D. Lee (Victoria Dawn). "Waste heat reclamation in aircraft engines". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/97318.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (pages 94-96).
Introduction: Rotorcraft engines can lose up to 70% of the potential chemical energy of their fuel as waste heat. Harvesting this waste heat and converting it to useful work would improve the efficiency and power output of the engine. Figure 1 shows two possible engine systems in which a secondary engine could be used to harvest waste heat. For the gas turbine engine in Figure 1A, the main source of waste heat is the enthalpy of the engine's exhaust gases. In the case of the spark ignition engine in Figure 1B, there are three sources of waste heat: the enthalpy available in the exhaust gases, the heat rejected by the coolant loop, and the heat rejected by the oil loop. For each engine system, the heat from waste heat engine is rejected to the ambient air. Possible candidate systems for waste heat recovery include closed cycle systems such as the Rankine and Brayton engines. Rankine engines typical use water as a working fluid. The performance of water-based Rankine engines suffer from low pressures in the working fluid at the temperatures of the ambient and, therefore, require large low pressure expanders and condensers to operate efficiently. Organic working fluids have higher vapor pressures and can be used in Rankine engines instead of water. The higher vapor pressures of these fluids allow the use of smaller expanders. However, organic working fluids are limited to temperatures below 250 C, which is substantially lower than the typical temperatures available in the waste streams. Brayton engines can operate at higher temperatures using inert gases such as helium and argon as working fluids. In either of these engines, the turbomachinery and heat exchangers must remain leak tight as the working fluid is cycled through at high temperatures and high pressures. As a consequence of this requirement, these cycles will not be considered further in this work. Thermoelectric devices, on the other hand, do not require leak tight passages or turbomachinery. These are compacted and are expected to have a higher reliability since they have no moving parts. These advantages have motivated this study on thermoelectrically-based waste heat engine. For a thermoelectrically-based waste heat engine to be feasible, it must be capable of absorbing and rejecting large amounts of heat in part to compensate for the low efficiencies of thermoelectric materials. It must also be light weight and compact to address concerns of power to weight ratios and space constraints in rotorcraft. Therefore, the waste heat engine must be designed to minimize thermal resistance while also minimizing the mass and volume of the heat exchangers.
by Victoria D. Lee.
S.M.
Paxson, Adam Taylor. "Condensation heat transfer on nanoengineered surfaces". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67630.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (p. 69-74).
This thesis presents a series of three related studies with the aim of developing a surface that promotes robust dropwise condensation. Due to their remarkably low droplet adhesion, superhydrophobic surfaces were investigated for application to dropwise condensation. Although precise model superhydrophobic surfaces were necessary to gain insight into these phenomena, it was recognized that wide-scale implementation necessitates a surface that can be mass-produced at an industrial scale. To this end, anodized metal oxide surfaces were pursued as candidate condenser materials. First, a study was performed to determine the precise conditions leading to the transition between wetting and non-wetting states. By depositing pendant drops of various sizes on a superhydrophobic surface and observing their wetting behavior, a hitherto unknown mechanism for wetting transition is reported. A new phase diagram was developed which shows that both large and small droplet can transition to wetted states due to the new deceleration-driven and the previously-known Laplace mechanisms. It is shown that the attainment of a non-wetted superhydrophobic state is more restrictive than previously thought. Second, we investigate the large-scale fabrication of superhydrophobic surfaces via two different methods: solvent-induced crystallization of a thermoplastic polymer, and anodic oxidation of aluminum. Although the polymer surface as not able to withstand the high temperatures seen during condensation, the applicability of the anodized metal surface to dropwise condensation was further investigated. Third, to replicate the conditions of a typical power plant or desalination plant, an apparatus was constructed that condenses steam at pressures below 1 atm. It employs a vacuum chamber in which a surface is exposed to saturated steam at various pressures. The rig design and operating principles are explained, and the results of condensation tests on superhydrophobic anodized metal oxide surfaces are presented. It was found that although the metal oxide surfaces were able to resist wetting of macroscale droplets, they suffered from non-preferential nucleation and droplet growth. This led to the eventual growth of a macroscale Wenzel droplet, which proved to be difficult to shed from the surface.
by Adam Paxson.
S.M.
Aguilar, Alex. "Harnessing thermoacoustics for waste heat recovery". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/130213.
Pełny tekst źródłaCataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 25-26).
Environmental concerns and economic incentives have created a push for a reduction in emissions and an increase in efficiency. The U.S. Department of Energy estimates that 20 to 50% of the energy consumed in manufacturing processes is lost in some form to waste heat. The purpose of this study is to review the waste heat recovery technologies currently available in both commercial and research applications to determine how thermoacoustics may serve a role in furthering the use of waste heat recovery units. A literary review of the most common waste heat recovery units was compiled to determine the advantages and disadvantages of the different technologies by comparing components and their governing processes. An existing model of a thermoacoustic converter (TAC) was reviewed and a conceptual analysis written to suggest improvements for future experimental designs.
by Alex Aguilar.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
Nazari, Ashkan. "HEAT GENERATION IN LITHIUM-ION BATTERIES". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1469445487.
Pełny tekst źródłaChung, Eunna. "Stress Conditioning and Heat Shock Protein Manipulation for Bone Tissue Engineering". Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77212.
Pełny tekst źródłaPh. D.
Mlakar, Genesis. "Effects of Surface Engineering on HFE-7100 Pool Boiling Heat Transfer". Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1619036502968687.
Pełny tekst źródłaLaijawala, Vipasha, i Zhu Xiaomeng. "Prediction of Variation from Heat Treatment". Thesis, KTH, Industriell produktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232711.
Pełny tekst źródłaFöreliggande rapport är resultatet av ett examensarbete utfört på uppdrag av Produktionscenter vidScania CV AB i Södertälje. Värmebehandlingsprocessen för kronhjul är beroende av en betydandemängd parametrar som är komplexa att modellera. Syftet med detta examensarbetet är att genomanvändning av avancerad analys undersöka möjligheten att förbättra förutsägbarheten för härddjupetvid sätthärdning av kronhjul.Arbetet inleds genom att studera de steg som är involverade i sätthärdningsprocessen ochråmaterialets egenskaper. Området maskininlärning studeras och utforskas för att känna till desstillämpningar och vilka resurser som krävs för dess användning. För prognos av utdata utförsdataanalys för att hitta parametrar som påverkar processen. Dessa data samlas från olika databaser,sorteras och syntetiseras för att kunna användas för maskininlärning i Python. En regressions- ochklassificeringsanalys görs genom att använda redan existerande algoritmer för förutsägelse frånScikit-learn. Modellerna som erhållits utvärderas med hjälp av metrik och en klassificeringsmodellbefinns ha den bästa förutsägelsesförmågan. En utvärdering av teknik- och affärsvärde utförs för attbedöma modellernas prestanda.Denna studie resulterade i utvecklingen av ett grundläggande verktyg som kan göra förutsägelserom härddjupet vid sätthärdning, med vissa begränsningar. Dessutom drogs slutsatser med avseendepå olika parametrar som påverkar processens resultat.
Vaitekunas, David A. "An investigation of the effect of flow obstructions on critical heat flux, pressure drop and heat transfer". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/NQ57073.pdf.
Pełny tekst źródłaLall, Balwant Singh 1969. "Numerical simulation of buoyancy induced flow and heat transfer in a vertical channel with discrete heat sources". Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278169.
Pełny tekst źródłaBetancourt, Arturo. "Computational study of the heat transfer and fluid structure of a shell and tube heat exchanger". Thesis, Florida Atlantic University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10172609.
Pełny tekst źródłaA common technique to improve the performance of shell and tube heat exchangers (STHE) is by redirecting the flow in the shell side with a series of baffles. A key aspect in this technique is to understand the interaction of the fluid dynamics and heat transfer. Computational fluid dynamics simulations and experiments were performed to analysis the 3-dimensional flow and heat transfer on the shell side of an STHE with and without baffles. Although, it was found that there was a small difference in the average exit temperature between the two cases, the heat transfer coefficient was locally enhanced in the baffled case due to flow structures. The flow in the unbaffled case was highly streamed, while for the baffled case the flow was a highly complex flow with vortex structures formed by the tip of the baffles, the tubes, and the interaction of flow with the shell wall.
Vattøy, Bjørnar. "Techno-economic evaluation of heat-driven cooling solutions for utilization of district heat in Aalesund, Norway". Thesis, KTH, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-245232.
Pełny tekst źródłaStudiens syfte är att utvärdera den tekno-ekonomiska genomförbarheten av att implementera värmedrivna kylelösningar i byggnader knytna till Tafjord Kraftvarme’s fjärrvärmenetvärk i Aalesund, Norge. Uppvärmnings- och nerkylningskrav hittades vid at projictera två 4000 𝑚2 kontorsbyggnader enligt “Passive House and Low Energy Building” kriterier, inom ramen av energikrav i TEK 17 byggnadsförordningar (Standard Norge, 2012) (Norwegian Building Authority, 2017). Passande nerkylnings- och uppvärmingsutrustning, både elektrisk och värmedriven, blev dimensionerande baserad på toppbelastning till de projicerade byggnader, och den tekniska och ekonomiska information tagen från utrustningsdistributörerna. LCOE-analysen visar att den värmedrivna nerkylningslösningen kan vara konkurrenskraftig ekonomisk sett, i variabel utstreckning, med de elektriska drivna lösningarna om varmebehovet är lågt eller vid at använda subventioner eller prisnedsättning på fjärrvarme som används för kylning. Nerkylningslösningen med torkmedel kan även vara konkurrenskraftig med den elektrisk drivna även utan subventioner eller prisnedsättning på fjärrvarme. Det är huvudsakligen på grund av dens förbättrade värmeåterhämtning som reducerar uppvärmningskraven. Absorptionskylaren å andra sidan, har både högre ströminmatning av fjärrvarme medan den är i gång och är därför mindre konkurrenskraftig utan subventioner eller prisnedsättning på fjärrvarme som används för kylning. I de utforskade byggnadsfallen kräver absorptionskylaren antigen subventioner eller prisnedsättning på fjärvarme för att kunna konkurrera med den elektriska kylmaren, medan det krävs både för att kunna konkurrera med värmepumpelösningen. Med ökande uppvärmingskrav blir de värmedrivna lösningarna som använder fjärrvarme som värmekälla mindre konkurrenskraftiga jämfört med värmepumpelösningarna. Detta på grund av de milda vintrar i Aalesund som leder till att värmepumparna kan köra med en COP på 2-3 medan den anses vara 1 for lösningarna som brukar fjärrvarme. Andra viktiga faktorer som inte ingår i LCOE-analysen är pålitlighet och miljöaspekten. Ingen av de värmedrivna nerkylningslösningarna andvänder något miljöovänligt köldmedium och underhållet av nerkyningsmaskiner är minimalt. Maskinernas livsläng är beräknad till 20 år för torkmedelkylaren och 40 år för absorptionskylaren, jämfört med 15 år för värmepumparna och den elektriska kylaren. De värmedrivna nerkylningslösningarna kan därför anses vara mer pålitliga både beträffande reglering av köldmedium och underhåll samt livslängd. Ytterligare en viktig faktor är att de värmedrivna nerkylningslösningarna, jämfört med värmepumplösningarna, kan vara et livskraftig alternativ, både med hänsyn til den ekonomiska faktoren, miljöfaktoren och pålitligheten och borde därför tas hänsyn till vid implementering av uppvärmings- og nerkylningsutrustning i byggnader knytna till fjärrvärmenätet.
Treiss, Stephanie. "TIME-DEPENDENT SURFACE TEMPERATURE and HEAT FLUX MEASUREMENTS on a SINGLE CYLINDER ENGINE HEAD and LINER". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512061036731254.
Pełny tekst źródłaLiu, Xuezhi. "Combined analysis of electricity and heat networks". Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/57830/.
Pełny tekst źródła